Seagate EXOS ST20000NM002C 20TB, 4kn two = success, two = nope! (Resource busy)

[tech20k]

Strange, I was able to convert two out of four drives to 4kn. One on an LSI 9361-16i in JBOD mode, but it gave me lot's of resets errors in the logs, which took over an hour to complete. The second one directly to the SATA port, which took about a couple of minutes. Then, I tried two more drives: ST20000NM002C Rev SN04 (identical) and I got:

open: Resource busy
open failure
Error: 16 - Resource busy
Error: Could not open handle to /dev/sda

Tried rebooting, tried a different sas card (LSI SAS2308). For some reason these apparently identical drives won't work. There is no indication that the OS is restricting access to these drives.

Command used:

./SeaChest_Format_linux_x86_64 -d /dev/sdb --setSectorSize=4096 --confirm this-will-erase-data-and-may-render-the-drive-inoperable

[tech20k]

Solved: it turned out these two drives were part of an mdadm array. I had used a disk wipe tool that didn't remove the mdadm superblock. Solution: stop the array then run the above command and/or use mdadm --zero-superblock /dev/sdX so you don't run into this problem later.

[vonericsen]

I'm glad you were able to figure this out!
I did not know this was something that could happen if a RAID superblock isn't removed.

[tech20k]

It wasn't the superblock. UDEV was starting the array. I didn't check my /dev/md directory. In some cases you won't get anything there and need to do an ls /dev/md* to make sure.